Variable pitch propeller



March 25, w47. 'W, W VERTS 2,417,917

VARIABLE FITCH PROPELLER Filed Feb. 1, 1944 2 Sheets-Sheet 1 l FLQQE.

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VARIABLE FITCH PROPLLER Filed Feb. 1, 1944 Y 2 Sheets-Sheet 2 MAXJMTCH MINIMUM FITI'H lrwffrvbofv 69 9 WaZferWEl/ers Patented Mar. 25, i947 orrlcs to variable pitch pro- My invention relates pellers.

:en important objectr of the invention is to provide a propeller of the above mentioned character having the pitch of the blades increased by the'action of centrifugal force upon the blades, whilesuch pitch is `decreased due to the action of the air 'pressure upon the blades caused by the driving rotation of the blades and aided by the suction action upon the front surface of the blades due to the camber of the blades.

A further object of the invention is to provide a propeller of the above mentioned character, wherein centrifugal force and the air pressure upon the blades, work in opposition to each other, thereby causing the pitch of the blades to be automatically increased, as the air pressure is reduced, when the elevation of the aircraft increases.

A further object of the invention is to provide a propeller of the above mentioned character so CIK constructed that the pitch or" the blades is in creased beyond the maximum driving pitch, when the aeroplane is travelling with the engine dead, thus feathering the blades.

e. further object of the invention is to provide means for mounting the blades upon the hub, for

a powerful connection to limit the outward radial movement oi the blades beyond the selected maximum diameter.

A further object of the invention is to provide a connection between the blades and the hub embodying intertting rings having contact relation with the hub, and aiording a strong and simple construction. K.

A further object of the invention is to provide an adjustable pitch propeller formed of relatively few parts, and which is of simple construction, reliable in operation, and may be manufactured cheaply. y

Other objects and advantages of the invention will be apparent during the course of the followingl description: u

' In the accompanying drawings forming a part of this application, and in which like numerals are employed 'to designate llike parts throughout the same,

Figure 1 is a side elevation of a variable pitch propeller embodying my invention. I

Figure 2 is a front edge elevation of the same,

Figure 2a is a section taken on the line 'la-2a of Figure 2,'

3 3, Figure 2,

.Figure 3 is a longitudinal section taken on line Figure 4 is 'a horizontal section taken on line il-ll of Figure 1, l f

Figure 5 is a diagrammatic viewshowing the parts in the position they loccupy when the blades are at the power minimum position,

Figure 5a is a transverse section through the blade showing the same at the power minimum Ditch,

Figure 6 is a diagrammatic View showing the position that the parts'occupy when the blades are in the power maximum pitch position,

Figure 6a is a transverse section through the blade showing the 'power maximum pitch,

Figure 7 is a diagrammatic view showing the position that theparts assume when the blades are in the non-power maximum pitch or feathered position, f f y i Figure '7a is a transverse section through the blade showing the non-'power maximum pitch,

Figure 8 is a side elevation of the propeller embodying a modie'd form ofthe invention, showing the blades in the outer-radial portion,v v

Figure 9 is a front end'elevation of the same,

Figure 10 is a radialsection taken on line Ile-I 0 of Figure 9, f Y Y v Figure 11 is a vertical section taken onv line il-lI of Figure 8, the rings occupying the outer position with respect to the hub, when the blades have the maximum pitch,

Figure 12 is a similar view, showing the rings in the inner position that they have vwith relation to the hub when the blades have the minimum pitch, v Figure 13 is a section taken on line I3-I3 of Figure 1l,

Figure 14 is a diagrammatic View showing the relative position between the driving arm and blades when the blades have the Vmaximum pitch,

and

Figure 15 is a similar view showing the relative position between the driving arm and blades vwhen the bl'adeshave the minimum pitch.'

Inthe drawings, wherein for the purposeA of illustration, are shown preferred embodiments of my invention, attention being'called to Figures 1 to 7, the numeral Ill designates a hub or rotary driving member'to be connected with or mounted upon the crank shaft of the engine. This hub or member may have a bore I I to receive the end of the crank shaft', which is rigidly held within the bore. t Y

rllhe numeral I2 designatespropeller blades of any well known or preferred type, having axes I3 upon which the Ablades turn to vary their pitch.

The blades have 'the usual front cambered faces 3 I4, leading edges I5 and trailing edges IB. The propeller when power driven rotates in the direction of the arrow, Figure 2. Each blade l2 has a tubular shank I'I at its inner end formed integral therewith, and this shank is rigidly mounted in a radial sleeve IS, by any suitable means. There are two radial sleeves which are diametrically oppositely arranged. The tubular shanks I1 are slidably mounted upon radial guides or supports IS, preferably formed integral with a sleeve 20, which in turn is slidably mounted upon the driving member or hub I I to move longitudinally and turn with relation to the hub, as shown. A wear sleeve ZI is preferably arranged between the radial guide or support I9 and each tubular shank I'I, to take up wear, and which may be removed, when desired. The wear sleeve 2 I prefer- 1 ably projects radially inwardly beyond the shank Il' and the inner end of this wear sleeve is spaced from the sleeve 2l), as shown at 22, and there is a space 22', at the outer end of the guide or support I9, as shown. 1

The numeral 23 designates a link or arm, which is provided at a point equidistantly spaced from its ends with-an opening 2d, for receiving the reduced end 25 of the driving member II, carrying a nut 25 for clamping the link or arm 23 to the driving member or hub I I. The arm 23 is therefore rigidly Vmounted upon the driving member or hub II to rotate therewith and extends for equal distances, radially, upon opposite sides` of the member or hub II. The link or arm 23 is provided at its opposite ends with spherical sockets 21,1to slidably receive balls 28, carried by Shanks 29, which are rigidlymountedupon the sleeves I8, upon their front faces.v `Attention isy called to the fact that the link or arm 23 is connected with the blades I2 through the medium of the sleeves I8 and associated elements,'at the points or centers ofthe balls 23, which are spaced from and disposed in advance of the axes I3, Figure 1. Disposed at'the rear of the blades I6 is a linkl or arm 33, having an opening 3|, at a point equidistantly spaced from its ends, and this opening slidably receives the drivingmember' or hub l I. The link or arm 3! is provided at its: opposite Aends with spherical sockets 32 slidably receiving balls 33 carried by Shanks y35, rigidly attached to the sleeves I8. The link or'arm 30 extends for equal distances upon opposite sides oi the driving member or hub .IL Thelink or arm30 is substantially identical with the link @or arm 23. Each link 23 and 39 is formed in connected longitudinal section s..- The` link or armI 30 is .pivotallyconnected with the blades I2 at the points or centers of the balls 33, which centers are spaced from and disposed rearwardly ofthe axes I3, Figure 1.

Y The operation of'the'virst form of propeller is as follows:

. `When thepropeller is rotated at a given speed atA sea level, itis operating under the maximum air pressuredue to ,the driving action of the propeller. The blades V,I 2* will then have the minimum-pitch. This is due to the fact that the air pressure acting upon the trailing portion of the blades 112, turnsthem upon theirv axes I3, in oppositiontothe action of centrifugal force which tends to bodilyshift the blades radially outwardly. Thisturning movement of the blades upon their axes I3 tojreduce the pitch is also aided by the suction action upon the front face of the blades due tothe camber of theblades. When the blades y areat the minimum pitch, link or arm 23 is in- 4 the axes i 3 of the blades, while link or arm 39 is inclined toward the trailing edges I3 of the blades and is angularly disposed with respect to the axes I3. These links or arms 23 and 30 are inclined in opposite directions with relation to each other, and being inclined with respect to the axes i3, the sleeves i8 are therefore iree to move radially and inwardly upon the guides or supports i5, until the ends of the wear sleeves 2l contact with the sleeve 23. When the aeroplane rises to a higher elevation, the air pressure acting upon the blades I2 due to their driving action, is reduced, and centrifugal force then moves the blades V' radially outwardly. This radial outward movement of the blades I2 causes them to swing upon the walls 2S, as they move outwardly,

- and the balls 33 turn the link or arm 3B upon the driving member or hub II until its longitudinal axis is in aiignment with the axes I3 of the blades. The longitudinal axis oi the link 33 is now in alignment with the longitudinal axis of the link 23. When the blades move radially outwardly due to the action of centrifugal force, they turn about the balls 28 so that their longitudinal axes are brought into alignment with the longitudinal axis oi the link 23. The maximum pitch of the blades i2 is reached when the longitudinal axes of .the links 23 and 33 and the axes I3 of the blades are all in alignment, the ball and socket joints then preventing any further radial outward movement of the blades.

When the engine goes dead, and the aircraft is still traveling, the blades being in any position between the minimum to the maximum driving pitch, the air pressure acting upon the front face oi' the blades will turn the blades upon their axes i3 to increase their pitch beyond the maximum driving pitch, thus causing the propeller to be feathered. When this occurs, the link 23 is angularly arranged, Figure 7, but extends in an opposite direction to that shown in Figure 5,

' since it extends toward the trailing edges of the clined toward the leadingedges I5 of the` blades,

and ishence'angularly :disposed with respect to The numeral 33 designates blades, preferably Y identical lwith the blades l2. The blades 38 have turning axes 39. These blades 33 have leading edges M3, trailing edges ll and front cambered facesv d2. The propeller is rotating in the direction'of the arrow, Figure 9. The blades 38 turn upon their radial axes 33 to vary their pitch; The blades 33 are provided at their inner ends withfshanks A3 and lili.- Rigidly secured to the shank d3 is a radial shank 6.3, having a ring 4S rigidly secured thereto. Rigidly secured to the shank lf-l is a radial shank 4l, having a ring 48 rigidly secured thereto. The rings 46 and 4S intert, each ring extending through the other, adjacent to the radial shank. At the radial shank 5, ring 43 has a radial pin 49 pivotally mounted in a radial recess 50, formed inthe ring d. At the shank el the ring 48 has a radial pin SI, pivotally mounted in a radial recess52,

Y formed in the ring d3. The rings 46 and 48 are adapted to turn upon the radial pins 49 and 5I,

and these radial are alignment with the axes 39. rIhe tubular hub -35 extends through the rings l5 and 4d, and contacts with the portions .of these rings remote from the radial shanks .4i-S and ill.

i Arms 52 extend `forwardly and generally axially of the tubular hub 35i and are rigidly secured to the 'radial Shanks iii 'and il. rfhese arms have at their forward ends, ball and socket connec tions 53, with. sleeves dfi, which are slidably mounted upon the radial dri-ving shaft or arm V3d, to turn thereon and move longitudinally thereof.

The operation of the propeller is as follows:

rEhe propeller is driven counter-clockwise,'Figure 9, andthe air-pressure acting upon the rear faces of the blades 3S, and the action oi the camber at the front faces Aof Athe blades, turn the blades di upon their axes 39 to reduce the pitch of the blades. At sea level, the blades would have the minimum pitch and the shortest radius. The radial `driving shaft or arm '36 isnow inclined with respect lto the axes 3d of blades. This is indicated diagrammatically in Figure l5. W hen the blades turn upon their axes to the minimum pitch, the

curved ends the rings il?, and. ed remote from .i

their Shanks, ride upon the curved surfaces of the cylindrical hub whereby lthe rings have their Shanks lid and al drawn `radially inwardly, thereby shortening the radius of the blades Si?,

Figure il.v When the aircraft rises to a higher 1" be produced, the blades turn upon their axes 39 to increase their pitch, the ends of the rings it and i3 turning about the curved face oi the tubular hub ASziwhereby the shanks t5 and Lil move radially outwardly, Figure 12. When the maximum pitch of the blades is obtained, the shaft or arm is in alignment with the axes 39er blades Figures '3, `9, and 14. When the Shanks l5 and el move radially inwardly and the pitch of the blades is reduced, the rings i5 andj t8 contact at A, and are spaced from the hubfi at E. When the shanks dii and il move radially outwardly and the pitch of the blades is increased, the rings d5 and i8 are spaced at, A and contact with the hub t5 at B.

The radial driving shaft or arm 3S serves to impart rotation from the hub 3d to the blades and Vto also hold the blades against improper axial movement -uponthe hub. 'The rings iE and d8 having their ends slidably engaging the curved face of the hub Sd, effect the inward radial movement of the bladealwhen their pitch is decreased, and increase the pitch of the blades when they are moved radially outwardly by centrifugal force. The rings 45 and 43 coact with the hub 35 to forma powerful connection to hold the blades against radial movement in an outward direction beyond the selected maximum diameter.

While the propellers are designed primarily for use on aircraft, they may be used for other purposes, such as upon boats, or upon windmills.

It is to be understood that the forms of my invention herewith shown and described are to be taken as preferred examples of the same, and that various changes in the shape, size, and arrangement of parts, may be resorted to, without departing from the spirit of my invention or the scope of the subjoined claims.

Having thus described my invention, I claim:

1. In an automatic variable pitch propeller, a

6 rotary driving member, propeller blades having turning axes, means to mount the blades upon the driving member to simultaneously move radially and turn upon their axes with relation thereto and to move axially of the driving member, said means having a camming action with the member to drawV the rings and extending axially of the hub, a

driving arm mounted upon the hub, sleeves slidably mounted upon the driving arm, and universal connections between the sleeves and the arms secured to the rings.

3. In an automatic variable pitch propeller, a hub, propeller blades having turning axes, interfitting rings mounted upon the hub, radial shanks carried by the rings and secured to the blades and in alignment vwith the axes of the blades, a pin for pivotally connecting the end of each ring remote from its shank with the other ring adjacent to the shank of the other ring, the pin being inalignment with the axis of the blade, a driving arm carried by the hub, and devices connecting the driving arm `with the Shanks ofthe rings.

4, An automatic variable pitch propeller, comprising a rotary driving member, propeller blades, means to mount the propeller bladesupon the driving member to simultaneously move radially and turn upon vtheir axes with relation to the driving member while the driving member is rotating, the outward radial movement of the blades being due solely to the action of centrifugal force and the turning movement of the lblades upon their axes to reduce their pitch being due solely to the action of air pressure upon the blades, said means including loops receiving the driving member therein, said loops interfltting with each other and having cam portions providing a cam action with the rotary member to draw the blades ra dially inwardly when they are turned upon their aXes to reduce their pitch, the cam portions having a camming action with the rotary member to turn the blades upon their axes in an opposite direction to increase their pitch when the blades are moved radially outwardly by centrifugal force, and driving connecting means between the rotary Y member and the blades.

5. An automatic variable pitch propeller, comprising a rotary driving member, propeller blades, means to mount the propeller blades upon the driving member to simultaneously move radially and turn upon their axes with relation to the driving member while the driving member is rotating, the outward radial movement of the blades being due solely to the action of centrifugal force and the turning movement of the blades upon their axes to reduce their pitch being due solely to the action of air pressure upon the blades, said means including substantially iiat loops receiving the rotary driving member and extending generally transversely of the driving member, said loops interfltting so that the end of each loop remote from its blade engages the rotary member while its opposite end is held out of engagement with the driving member, the ends of the loops engaging the driving member having cam portions providing a cam action with the rotary mem-V` ber to draw the blades radially inwardly when they are turned upon their axes to reduce their pitch,'the camportions providing a camming action with the rotary member to turn the blades upon their axes in an opposite direction to increase their pitch when the blades are moved radially outwardly by centrifugal force, and driving connecting means betweenthe rotary member and the blades.

. 6. In a propeller, a rotary driving member, propeller blades arranged near the driving member and having turning axes arranged permanently radially of the driving member, loops attached to the inner ends of the blades and receivingthe driving member through them, said loops interiitting with each other and having turning axes extending radially of the driving member and in alignment with the radial turning axes of the blades, each loop having an inclined part-arranged remote from the bladeof the loop, said linclined part having a camming action with the driving member when such blade is turned upon its axis to reduce the pitch of the blade, driving means mounted upon the driving member to rotate therewith, and a device connected withV each blade and extending generally axially of the rotary driving member and connected with the driving means. y

7. In an automatic variable pitch propeller, a substantially cylindrical hub, propeller bladesarranged near the hub and having variable pitch turning axes arranged radially of the hub, rings secured to the inner ends ofthe blades and receiving the hub therein, said rings intertting with each other and havingr turning axes disposed radially of the hub and in alignment with the turning axes of the blades, each ring having its part remote from the blade of the ring engaging with thehub for producing a camming action which drawssuch blade radially inwardly when the blade is turned upon its axis to reduce its pitch, a driving member mounted upon the hub to rotate therewith, and means connecting the blades with the driving member, vsuch means swinging with the blades when they turn on their axes.

8. In an automatic variable pitch propeller, a rotary driving member, blades arranged near the member and having variable pitch turning axes arranged substantially radially of the member, loops connected with the inner ends of the blades and receiving the rotary member therein, said loops interiitting with each other and having turning axes substantially radial of the driving member and in substantial alignment with the axes of the blades, said loops slideably engaging the driving member to turn thereon and move axially thereof, a driving device mounted upon the driving member to rotate therewith and held against axial movement with relation to the driving member, and elements extending generally axially of the driving member and attached to the blades and connected with the driving device.

9. In an automatic variable pitch propeller, a driving member, propeller blades arranged near the driving member and having variable pitch turning axes arranged substantially radially of the driving member, loops attached to the inner ends of the blades and receiving the driving memyber therein, a pin for pivotally connecting the end of each loop remote from its blade with the other loop, the pin causing the loops to turn upon an axis substantially radially of the driving member, the loops being slideably mounted upon .the driving member, each loop having a camming action with the driving member at a point remote from the blade of such loop to draw such blade radially inwardly when the blade turns upon its axis to reduce its pitch, a driving device mounted upon the driving member, and means connecting the driving device and blades.

WALTER W. EVERTS.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS FOREIGN PATENTS Country Date French Jan. 23, 1937 Number Number 

